The purpose of this application is to acquire an updated confocal microscope for the established Boston University School of Medicine Confocal Microscopy Core Facility. The facility currently houses a Leica confocal laser scanning system that was purchased in 1991. Funds are requested to purchase an Leica TCS NT confocal image analysis work station with an inverted microscope. The option of placing the scanner on an upright microscope is also included, but will be funded from institutional support. The software includes the 3D and physiology programs as several researchers plan to obtain time lapse recordings of live tissue stained with vital dyes, calcium or pH indicators. Currently the Anatomy and Neurobiology Department has allocated space for the microscope, and the Dean of Medicine, Graduate Dean, and Departmental Chairs have promised institutional support. The institutional support will include money to purchase an additional upright microscope and other accessories. Extensive data has been collected on the current user group from 1992-1996. The existing confocal system is used over 800 hrs/year with many months topping 100 hrs. Five primary and eight secondary researcher groups have been identified that will need the new equipment for a broad range of projects. The researchers span many age groups, from young investigators to senior scientists. Most participants have current PHS grant support, and are looking forward to enhancing and extending their research with the equipment with this new microscope for the core facility. Our current machine is only 6 years old, however, the computer system is obsolete and simple repairs take extensive time. In addition, it is limited in the types of specimens that can be viewed as it is equiped with only an argon laser and two photomultiplier tubes.